What Is Guanidine?
Guanidine is an organic compound with the molecular formula CH5N3. It is also known as imido carbonic acid diamide, and its CAS number is 113-00-8.
It has a molecular weight of 59.07, a melting point of 50°C, a boiling point of 160°C (decomposition), and exists as a colorless crystalline powder at room temperature. It is strongly basic, with an acid dissociation constant pKa of 12.5. It is readily soluble in water and also soluble in ethanol, methanol, and dimethylformamide.
It is a chemical found in nature in mushrooms and earthworms, and is also detected in human urine because it is produced by protein metabolism.
In air, it absorbs carbon dioxide, which changes its properties, so it must be stored in a tightly sealed container.
Uses of Guanidine
Guanidine is used as a raw material for plastics and explosives.
In addition, due to its ability to easily form hydrogen bonds, salts of guanidine are used in a variety of fields. For example, the hydrochloride salt (guanidinium chloride) and the thiocyanate salt (guanidine thiocyanate) are often used as protein denaturants in the biochemical field.
Synthetically, guanidine nitrate is used as an ingredient in gunpowder, and guanidine hydrochloride is used as a synthetic ingredient in pharmaceuticals and dyes.
Guanidine phosphate is used as an excellent fire retardant for paper and wood. In addition to being highly flame retardant, guanidine phosphate is believed to prevent moisture absorption and iron corrosion.
In recent years, research has been conducted to use guanidine as an alternative to fossil fuels. Guanidine and the guanidino group are strong bases, and there are many derivatives of guanidine that are used as strong bases in organic synthesis.
Other applications include raw materials for synthesizing photographic materials, disinfectants, and many other fields.
Properties of Guanidine
1. Chemical Properties of Guanidine
Guanidine is stabilized by delocalization of the positive charge of the conjugated acid on the three nitrogens due to resonance, and exhibits strong basicity. Thus, under physiological conditions, it exists as a protonated +1-valent cation (guanidinium ion).
When heated to 160°C, it releases ammonia and converts to melamine (C3H6N6).
2. Derivatives of Guanidine
A compound containing guanidino groups is arginine, a type of amino acid. Arginine is a substance known to play an important role in proteins, such as binding to DNA.
Among natural product alkaloids, compounds containing guanidino groups biosynthesized from arginine are known, and many of them have strong physiological effects, such as saxitoxin and tetrodotoxin.
In addition, nitroguanidine, in which a nitro group is substituted for guanidine, is a substance known as a raw material for explosives.
Types of Guanidine
Guanidine pure substances are sold primarily as reagent products for research and development; they are sold in volumes of 5 g, 10 g, etc., and are compounds that are sometimes stored under refrigeration due to their tidal properties.
Guanidine is more commonly sold as a salt than as guanidine itself. It is available as a reagent product for research and development and as an industrial chemical.
Available reagent products for research and development include guanidine hydrochloride, guanidine nitrate, guanidine thiocyanate, guanidine phosphate, guanidine carbonate, guanidine sulfamate, and guanidine hydrobromide.
Compounds with biochemical applications, such as hydrochloride and thiocyanate, are often available in grades such as molecular biology/biochemistry, so it is necessary to select the product grade that best suits your application. Types of capacities commonly exist, such as 25g, 100g, 500g, etc.
Similarly, guanidine hydrochloride, guanidine nitrate, guanidine phosphate, guanidine carbonate, guanidine sulfamate, and others are available as industrial chemicals.
Products such as 60% aqueous hydrochloride solutions may also be available. These products are used as raw materials for organic synthesis, raw materials for fiber treatment agents, raw materials for bioprocessing, and raw materials for clinical laboratories.